Drier



Dec. 8, 1931.

l... G. RGOWAND ET AL.

DRIER Filed June 3, 1929 3 Sheets-Sheet l BY M M ATTORNEY Dec. 8, i931.

l.. G. ROWAND ET AL 15mm med June 3, 1929 l i l h.

" Edwin-@EMF- De@ 8, 1931. L. G. RowAND ET AL 1,835,530

DRIER Filed June 3, 1929 5 Sheets-Sheet 3 -ff/ fr ATTORNEYS vention relates Patented Dec. 8, 1931 UNITED A *SVTA'TES LEWIS Gr. ROWAND', OF BOOKLYN,NE`I

Application filed June S,

arrangement of apparatus for drying finely divided material. y More particularly the 'nr to tower driers of the type used for drying-'finely `divided ores, concentrates andthe like, and in which drying gases and materials tobe dried are passed through the drier in counter-current relationship.

` According to some present practices, tower driers are provided with stationary baffles extending between opposite Aside walls of the towerifor retarding'the downward movement of materials to be dried. In suclrap-` paratus bridging ofthejwet material between adjacent bales and 'between the bafrles and the tower wallsis unavoidable. and troublesome even when a considerable proportlon'r of the wet materialpisrelatively coarse, and it is particularly common and troublesome when the material being dried is rela-tively line.V The .bridging of materials, in driers prevents intimate contact ofthe drying gases with the wet material and results in a great loss in etiiciency througl loss of heat dneed capacity ofthe drier. n Y

The present invention contemplates ,the provision of improved battle means for dry. ing apparatus b y means of which objectionable bridging 'of wet materials may be prevented. yThe present inventionfurther contemplates the provision of improved drying apparatus comprising a drying chamber. means for to the drying chamber, means for generating and introducing drying gases into the drying chamber, andv improved baille means for bringing the tinely divided materials into 4intimate Contact with the drying gases.

j Complete drying apparatus constructed in accordance with eil-ably comprises a vertical dryingtower hat ing rotarybaiiles mounted therein, a combustion chamber arovided w-ith a travelling grate stolrer, a gas flue-for supplying hot gases to the vertical drying' tower and having one or more passages communicating with the interior of the vertical dryingtower atappropriatey points, and feeding means adjacent the top of the vertical tower so constructed g YORK,`AN`D JACKSON S. PEL NEW JERSEY, ASSIGNO'ES I3 TELE NEW JERSEY ZT.

and. ref,

feeding finely divided ,materials the present invention pref-- ETT, OF FRANKLIN,

NC COMPANY, `Gl NEW YORK, N. Y.,

1935?-9. Serial N0. 567,890.

and arranged that the material to be dried may be admitted to the interior of the drier without permitting ingressor egress of gases. vThe baliles are preferably arranged in vertically `spaced groups and mounted in the upper portion of the drying tower. One or more passages providing means of communication between the gas iue'andthe interior of the vertical drying tower are provided in order to secure a'more uniform drying tem'- peratnre. @ne passage is preferably located adjacent the bottom of the tower and beneath the iowermost balli-es. Y A second passage may be located approximately midway between the top and the bottom of the tower and preferably admitsrgases to the interior of the tower between Vtwo adjacent groups of batlies. When two passages vare provided, the uppermostpassage is preferably smaller than the lowcrmost passage toprovidefor proper dis-l tribution of the l Means may be providedforregulating the sizes of the passages or for closing one of the passages in order to control the flow of heating gases.

'ihe provision of at least two vertically spa-ced passages for the introduction of hot is preferable in order to prevent condensation on the `incoming material of the vapors generated in. the hottest portions of the thier. 'The lowermost passage is preferablydisposed adjacent the bottom of the drying chamber, and the uppermost passage disposedwat such a point between the bottom and topof the drying chamber that the moisture laden gases passing upwardly may be maintained ata temperature sufficiently highto prevent condensation ofthe vapors before the gases are discharged. A separate combustion chamber may be provided for each entrance passage instead of a single combustion chamber and a 'flue communicating with the combustion chamber and all of the passages.

rShe combustion `gases for heating purposes may be obtained by burning any suitable type of material, such, for example, as coal, oil, or gas. ln the event that more than one combustion, chamber is provided, theymay all be fired with the same combustion supporting materials, or diflerentones may be fired with clined to cake `or i outer surfaces of the rim`;l

different materials. For example, for the sake of convenience in handling the combustion supporting materials and to eliminate heat losses which might result from conducting the'hot gases for 'any considerable distances, the combustion chamber communieating with the lowermost passage might be readily accessible and, therefore, might be conveniently fired with a solid material,

ing with the uppermost passage might be made less accessible and, therefore, might b'e fired with a flui d material which can be readily conducted to desired points. The pro# vision of separate combustion chambers would permit more accurate control' ofthe supply of hot gases. Thus, one yor more of the separate combustion chambers may be cutout when a lesser number will provide suliicient heat. In such cases, 'the use of fluid combustion supporting materials inthe chambersmost likely to be'foundunnecessary at times is advantageous because of the ease with'wliich such lircsmay be cutout.V t

`lVhen solidv carbonaceous materials are used forl generating the drying gases, the use' of traveling grate stokers is highly advantageous.l The travelingI grate Stoker permits'better control ofthere and elimif nates losses of'time in cleaning lires.

The baffles arepreferably in the form of wheels with pockets Aformed yon 'the inner and outer surfaces of the rims.' The external diameters of the baille wheels are slightly less' than 'the width of the interior-of the upper portion of the vertical tower.l The rotary baille wheels maybe driven by any suitable means, such. for example, as outside chains and sprockets.

vStationary baflles may be used tion 'with the rotary bafll'es. j ballles may be'used in those portions ofthe upper part ofthe'drying chamber 'in which the material is normally wettest and most inin conjunc- Thns, ro'taiv balflesmay be used the chamber which partly dried condition'so that bridging tendency has been' eliminated.

The invention will .be better understood from a eonsiderationfof the following Vde-A scription, taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a vertical section of dryingapparatus embodying the invention;

. Fig. 2 is a vertical section taken substantially at right angles to that shown in Fig. 1 and showing tlie arrangement of battles;A

in thosev lower portions of Fig. 3 is a sectional plan showing the rela-v tive positions of the' feeder and baffles;

Figjfl is a fragmentary view of the rim of the rotary baille wheel, partly in section, `and showing the pocketsformed on the inner and bridge, and l stationaryv the material `reaches in a` the caking or Fig. 5 is a side elevation of a rotary baille wheel; and

Fig. G is an end elevation, partly in section, of a rotary baffle wheel.

' The apparatusshown in the drawings comprises' a verticalV drying tower 1()v supported upon a suitable foundation 11. Drying` gas generating means is disposed adjacent the bottom of the towerand comprisesV a combustion chamber 12, for solid carbonaceous material, provided with a travelling grate Stoker 13 and communicating with the interior of the drying tower through a flue 14 and vertically spaced passages 15 and 16. Means for feedingmaterial to Vbe, dried to the drying tower is'k disposed adjacent the top of the tower andvcomprises'achute 1f?, rotary feeder AE20, andfeed'hoppe'r 2l.

he dryingtower may be formed of any suitable material, such, for example, as bricks, or avmctal shell lined withbricks. The interior oftheupiper portion of the tower is rectangular inI plan.,v y lowerv portion of ythe drying `towernniy be of any desired outline,` and it is preferably provided with a lining or wall 22 ofheat refractory material whichl serves to. protect the outer walls from theheat'of the enterin gases and the dried material ywhich falls to the bottom of the Iingtovver. The portion ofthe' tower adjacent 'the uppermost gas entrance passage is also preferably lined with heat refractory materiali 'A plurality ofshafts 23, having wheels i Y i i enough to provide'clearance for the baille,

wheels during rotation, permit anyconsiderable quantity of mate,- rial to fall directly from the top tothe bottom of the tower.

The balflelsupporting shafts are spaced apart, vertically,"distances slightly greater than the radii of the baffle Y are staggered to ypermit the baille wheels on ea'chrshaft to extend into spaces between the bale wheels on the neXt adjacent shafts. The sidefaces of the intermeslring Abattle-wheels ar'e'spac'ed apartvand the side faces of the The. interior ofvr thev Thel'baflle supporting shafts are E tus. An excess baie immediately adjacent the tower walls are spaced from the walls only suliiciently to rovide clearance.

The bottom portion of the drying tower is provided with a discharge opening 25 communicating with a downwardly opening chute 26. A door 27 is pivotally mounted on the chute 26 and normally closes the dischargeY end of said chute. A hopper 3() is disposed beneath the chute 26 for receiving the dried material and directing it through the conduit 31 into suitable conveying apparatus (not shown).

The chute 17 of the feeding means extends through an opening in the side wall of the tower adjacent the top thereof. The discharge end of the chute 17 extends to a point immediately above the uppermost baille wheels and substantially midway between the vertical cente-r and a side wall of the tower. The rotary feeder 2O comprises a central shaft mounted for rotation about a horizontal axis and having blades 32 mounted thereon. The rotary feeder 2O is mounted within a casing which joins the chute 17 and the hopper 21 and the peripheral and end edges of the blades 32 are spaced from the walls in said casing only a suliicient distance to provide clearance. The rotary feeder 20 may be driven in any suitable manner.

The rotary baille wheels may be formed as integral castings, but they are preferably constructed of a number of separate pieces, which construction permits the selection of suitable types of materials for those portions which require special materials because of unusual conditions. Cast iron rotary baffle wheels have been used successfully, but it has been found that as a result of temperature changes cracks are developed in the rim portions. The present preferred type of the rotary baffle wheel consists of a semi-steel casting 33 comprising a hub and spokes, and. a rim 34 built up of structural steel plates and angles. rIhe spokes are provided with flanged end portions 35 and a steel band 36 is bolted or riveted or otherwise attached to the flanges 35 to provide a rim for the wheel. Steel angles 37 and 40 are attached to the inner and outer surfaces ofthe rim band 36,at the edges thereof. Steel strips 41 extend transversely between the upwardly projecting walls of the angles pockets on the inner and outer surfaces of the rim. The angles 37 and 40 and strips 41 may be attached to the rim 36 in any suitable manner, such, for example, as by bolts or rivets or welding.

In the operation of the apparatus shown in the drawings, material to be dried is delivered to the feed hopper 21 and fed to the drying chamber by means of the rotary feeder 20 and chute 17. The rate of feed will depend upon the capacity of the drying apparaof material may be 'main- 37 and 40 and formv tained in the feed hopper and this excess, in conjunction with the blades of the rotary feeder, functions to inhibit the ingress or egress of gases during drying operations.

The combustion apparatus is operated to produce drying gases at the rate and temperature required.

The baffle wheels are rotated slowly, about four revolutions per minute. Alternate pairs of baffle wheel supporting shafts are rotated in opposite directions. This method of operation results in the material following a tortuous path from side to side of the drying chamber as it passes downwardly therethrough, and prevents bridging of the wet material. The pockets formed on the rims of the baffle wheels serve to retain a large portion of the material being dried for considerable periods of time. This fact permits the maintenance of lower temperature in the drying chamber and permits the dischargeof dried material at lower temperatures. i

' The usual means for removing waste gases from the drying chamber may be employed.

We claim: j

1. Drying apparatus comprising a drying chamber, means for feeding material to be dried to-said drying chamber, means for introducing drying gases into said drying chamber, and bafile wheels having pockets formed on the inner and outer surfaces of their rims mounted in vertically overlapping relation for .rotation within said drying chamber.. 1

2. Drying apparatus comprising a drying chamber, means for feeding material to be dried to said chamber adjacent the top thereof, means for introducing drying gases into said drying chamber adj acent Y thereof, and a plurality of baffle wheels having pockets rim portions mounted for rotation within said drying chamber, the baffle wheels of one series extending into the spaces between the baffle wheels of the adjacent series.

3. In drying apparatus, a rotary baffle comprising a hub having radial spokes, a flat band rigidly attached to the ends of the spokes, angles fastened to` each edge of the band and having a flange extending radially outward, and strips extending transversely of the band and between the flanges, the arrangement being such as to define a series of pockets on the band.

4. In drying apparatus, al baflie comprising a wheel having a rim, and pockets formed on the inner and outer surfaces of said rim.

5, An apparatus for subjecting materials to the action of gases comprising a gas chamber, an inlet for introducing a gas at one end of the chamber, an outlet for the gas at the other end of the chamber, a plurality of series of space d rotatable baliie wheels located within the chamber between the gas inlet and outseries of spaced formed on their the bottom i let and having material-arresting means thereon, the Wheels of one series extending into the spaces between the baiile Wheels of the adjacent series, the arrangement being such that the axes of all the Wheels lie substantially in a common plane, and means for dischargingmaterial into the Chamber onto the baille Wheels.

6. An apparatus for subjecting materials to the action of gases comprising a gas eha1nber, an i nletfor introducing a lgas Within the ohalnber, an ontlet for removing;` the gas from the chamber, a pair of spaced battle Wheels within the chamber provided with materialarresting means, a baille Wheel mounted on a separate axis extending' into the space between and overlapping the pair of first-mentioned Wheels, said latter Wheel also being provided v. 'th material-arresting` means, the

Vwheels rbeing` so constructed as to provide an unobstructed opening for the passage ofthe gas through a substantial portion of their overlapping' area, and means for discharging material into the chamber onto the baille wheels.

7. An apparatus for snbjeetiingT materials to the aetion ot gases comprising a Chaniber, an inlet for introducing` a ,f as Within the Cham-ber, an outlet for removingT the gas from the Chamber, a pair of spaced baffle Wheels Within the Chamber provided with materialarresting means, a baffle Wheel mounted on a separate asis extending' into the space between and overlapping the pair of first-mentioned baille Wheels, said latter Wheel also being provided With material-arresting means, the Wheels being' so constructed as to provide an unobstructed opening for the passage of ,the gas through a substantial portion of their overlapping area, the axes of the Wheels lying substantially in a common plane and their oireumterenees extending' into close proXiinity With the Walls of the chamber, and means for discharging' material into the chamber onto the baffle Wheels.

In testimony whereof We aiiX our tures.

LEWIS G. ROVVANI). v JACKSON S. PELLETT.

signa- 

